This is the first year I've driven my IS in the winter at all, will probably be the last too! I think it's a decent winter car except for the ride height, just not enough ground clearance on it for the amount of snow we get. At least I only have to drive back and forth from work and it's a 5 minute drive.
As for the windshield chips, not bad here for that at all, no freeways or high speed roads in the city to really get that stuff thrown up.
so far no problems with ride height. My IS is all stock. This winter there's been a lot of snow early on so far but thankfully haven't gotten stuck yet. I've never had a problem with stonechips from rocks or sand on the roads.
Winter driving the IS is actually quite fun and a good learning experience...first time driving RWD in the winter